Molecular characteristics of multifocal invasive mucinous adenocarcinoma of the lung: Report of a rare case

Invasive mucinous adenocarcinoma (IMA) is an uncommon entity in the lung, with a poor prognosis. Multifocal IMA of the lung is even more unusual, and there is little experience with effective treatments. Herein, we present a case of multifocal IMA diagnosed in a 36 year‐old man by video‐assisted thoracoscopic surgery. A right middle lobe and a nodule in the right upper lobe were resected, as were mediastinal lymph nodes, leaving behind an autonomous right lower lobe nodule. To explore the feasibility of molecular treatment, next‐generation sequencing of genetic mutations was performed after four cycles of chemotherapy (pemetrexed + cisplatin). Ultimately, a KIAA 1468‐ RET fusion gene was detected at a disproportionate level (~67.3%), indicating that targeted therapy may be efficacious in treating this disease.